werner



(No Model.) 3 Sheets-Sheet 1.

E. A. WHEN-3R.`

BRIDGE.

No. 311,624. vPatented Feb. 3, 1885.`

WITNBSSES INVENTOR ATTORNEYS.

(No Model.) 3 Sheezs--Shees` 2.

E. A. WERNER.

BRIDGE.

No. 311,624. Patented Feb. 3,1885.

WTNESSS: l v INYENTRI L//U (A @MW BY Mgg ATTORNEYS'.

(No Model.)

E. A. WERNER.

BRIDGE.

No. 311,624. Patented Feb. A3, 1885.

INVENTR WITNESSES TTORNEYS.

N PETERS. Phulo-Lnhngmphw. Waxhmgwn. D. C.

iUNiTnn STATES PATENT @Erica i EMMERICHYA. WERNER, OF NEW YORK, N. Y.

BRIDGE.

SPECIFICATION forming part of Letters Patent No. 311,624, dated February3, 1885.

4 Application tiled April 27, 1882. (No model.)

To all whom t may concern:

Be itknownthat l, EMMERICH A. WERNER, of the city, county, and State ofNew York, have invented certain new and useful Improvements in Bridges,ot'which the following is a full, clear, and exact description.

The object of my invention is to provide a new and improved girder byintroducing a plain tension or compression chord with bowgirders.

Figures l and 2 are side' views of different forms of my improvedbridge. Fig. 3 is a detail side view ofthe lower part of one of the bowsofmy improved girder. Fig. 4 is a crosssectional View of the same. Fig.5 is a plan View ofthe same.

In bow-girders with joints at the top or crown and at the abutmentsathrust is eX- erted against the abutments, and it is well known thatthe chords of such bow-girders take up the horizontal thrust of the bowand the action of the bending forces or moments, whatever :may be themanner of loading or the kind of bracing used in the girder. lt is knownthat with moving loads the absolute value of the moments is, accordingto the position of the loads, alternately positive and negative; henceproducing alternately tension and compression strains in the chords, sothat in an ordinary bow-girder both chords must be constructed andadapted to resist compression as well as tension. The thrust of the bowis always a compression strain. I take this thrust out of the chords bycertain members introduced in the bow-girder. The action of the thrustis thus eliminated from thefchords, and now it remains to overcome thealternate positive and negative strains in the chords. As is known, thebending forces or moments acting in the chords are represented by thevertical reaction of the abutment and the vertical action ofthe load,less the bending generated by the action of the horizontal thrust of thebow. It is evident that as long as the latter is less than the formerthe total action of the bending moments will be positive; hence Icalculate the height of the bow at each point in such a manner that theaction or bending moments ot' the horizontal thrust will always besmaller than the action of the moment of the vertical forces-thevertical reaction and loads.

In calculating the height of the bow at each point in such a manner asto have the bending moment arising from the horizontal thrust less thanthe moment of the vertical forces, the moments in each point of thegirder are always positive, and the alternate positive and negativestrains will be reduced to positive or tension or compression strainsonly. Thus, if I provide a separate strut or chord running from theabutment to the top and taking up the complete horizontal thrust of thebow, and constructed and calculated in the manner above described, thechords of my new girder will be entirely independent of the action ofthe thrust, and the moments acting upon them will always bepositive-that is, the strains will at all times be tension andcompression-and a plain tension eye-bar chord can be used in the newgirder This involves the arrangement of the struts so that they shallform at the crown an angle, each strut shaped according to the formfound by the above-mentioned calculation. Moreover, in the new girderthe chords are entirely independent of the height of the crown of thebow above the abutments for one and the same kind of loading Myinvention relates only to the chords of bow-girders, and is entirelyindependent of the system of bracing or construction of the bracing,which may be of any desired kind.

In illustration, I have shown in Figs. 1, 2,

' and 3 my new girder comprising in each half a plain compression upperchord, b, a plain tension lower chord, a, and suitable bracing. A is aspecial strut extending from the crown- `joint to the abutment, andthechords a b, with their bracing, are mounted thereon and connectedthereto, so that the horizontal thrust of the girder is taken up whollyby the special strut A', and none is communicated to the chords.

ln the drawings the strut is placed midway between the two chords. It isscarcely necessary to say that it can be introduced in various otherways; also that the strut can coincide with one of the chords.

In a suspension-bridge, which is a reversed bow-girder, the methodsgiven above can also be applied for calculation.

The characteristic features of my girder are always that the moments inany part of the ICO girder are always positive, whatever may be theposition of the load, and the absolute value of the moments isindependent ofthe height ofthe crown-joint above the abutments for oneand the same kind of loading.

Having thus described luy-invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. The combination, in a boW-girder having Io joints atthe top and atthe abutments, of a plain tension and a plain compression chord and aspecial strut in union with said chords, substantially as and for thepurpose set forth.

2. In a bow-girder, the combination, with an upper plaincompression-chord and a lower plain tensionchorcl united to each otherby suitable trussing, of struts jointed together at the crown andjointed to the abutments, said chords and bracing being connected tosaid struts, as described, and suitable supports for the roadway,substantially as herein shown and i described, and for the purpose setforth.

8. In a bow-girder, the combination, with the two sections forming thebow, of struts jointed together at the crown and forming an angle, whichstruts are jointed to the abutments, and of suitable supports for theroadway, substantially .as herein shown and described, and for thepurpose set forth.

4. In a bow-girder, the combination, with the two sections forming thebow, of curved struts jointed together at the crown and forming a Gothicarch, which struts arejointed to the abutments, and of suitable supportsfor and described, and for the purpose set forth;

EMMERIGII A. WERNER. Witnesses: v GEO. D. IVALKER,

C. SEDGFWICK.y

the roadway, substantially as herein shown 35

